It is often necessary to exactly assess the depth of a blind hole. Existing measurement devices have a single hook on one end of a calibrated rod. The rod is inserted through the hole, and after the hook emerges through the opposite, distal wall, the rod is retracted until it abuts against the blind edge of the hole. The disadvantage of these devices is that hooking the edge of the hole through the far wall could be quite difficult, mainly when measuring smaller diameter holes.
For the foregoing deficiencies in the prior art, a new hole depth-measuring instrument that provides a fast and accurate measure is needed. There is a further need to have an instrument wherein the probe firmly engages to the distal edge of the hole, allowing a precise measurement of the depth of a blind hole.